diff --git a/openmc/plotter.py b/openmc/plotter.py
index c3b951ad89..85c4963a76 100644
--- a/openmc/plotter.py
+++ b/openmc/plotter.py
@@ -1,6 +1,3 @@
-# annotations package is required to enable postponed evaluation of type
-# hints in conjugation with the | operator. This avoids TypeError: 
-# unsupported operand type(s) for |: 'str' and 'NoneType' error
 from __future__ import annotations
 from itertools import chain
 from numbers import Integral, Real
@@ -126,7 +123,7 @@ def _get_title(reactions):
 
 
 def plot_xs(
-    reactions: Dict[str, openmc.Material | List[str]],
+    reactions: Dict[str | openmc.Material, List[str]],
     divisor_types: Iterable[str] | None = None,
     temperature: float = 294.0,
     axis: "plt.Axes" | None = None,
@@ -139,7 +136,7 @@ def plot_xs(
     divisor_orders: Iterable[int] | None = None,
     energy_axis_units: str = "eV",
     **kwargs,
-) -> "plt.Figure":
+) -> "plt.Figure" | None:
     """Creates a figure of continuous-energy cross sections for this item.
 
     Parameters
@@ -291,7 +288,6 @@ def plot_xs(
     return fig
 
 
-
 def calculate_cexs(this, types, temperature=294., sab_name=None,
                    cross_sections=None, enrichment=None, ncrystal_cfg=None):
     """Calculates continuous-energy cross sections of a requested type.